DESCRIPTION (Applicant's Abstract): Pediatric obesity is a prevalent and increasing condition in this country. Given its negative health effects, it is essential to identify environmental causes of pediatric obesity so as to develop the most powerful interventions and prevention efforts. Within the context of a "Mentored Clinical Scientist Development Award," the proposed research tests the hypothesis that greater amounts of Maternal Control Feeding Style (MCFS) cause (1) poor child caloric compensation and (2) increased child body fat. We call this the "Maternal Overcontrol" model of child eating and these studies do not allow for statements regarding direction of effect. Consequently, this model may not accurately depict a pathway by which pediatric obesity develops. We propose a twin study which more rigorously tests the "Maternal Overcontrol" model. We will study 88 twin pairs, 3-5 years of age, and their mothers. Forty-four pairs of each sex will be recruited, thus allowing us to test the hypothesized model separately among girls and boys. Within each gender, half of the twins will be monozygotic and half will be dizygotic. Measures of caloric compensation and total body adiposity will be taken on child subjects. Self-report and behavioral measures of MCFS, and general parental control (GPC), will be taken on mothers. Using structural equation modeling, we will test whether the observed data support the hypothesized "Maternal Overcontrol" model. This model will be tested against alternative models, including (1) a "child-driven" causal model in which child phenotypes elicit increased MCFS, (2) a "reciprocal" causal model, (3) a "genotype-driven" causal model in which a common genetic diathesis causes poor caloric compensation and increased adiposity in children, which in turn elicits increased MCFS, and (4) a "general parental control" model, in which GPC causes variation in child phenotypes. Standard statistical criteria will determine which model(s) are best "fit" by the observed data. This study will be conducted within the broader context of an expert-led training program. In the short-run, the candidate will receive personal instruction, "hands-on" training, and course work with experts in the areas of behavior genetics design and analysis, and the measurement of child caloric compensation and body composition. Leading laboratories, in and out of the home institution, will be training sites. In terms of long-term goals, the candidate will obtain the skills to successfully compete for advanced research programs (e.g., FIRST AWARD, RO-1) concerning environmental influences on child eating behavior and adiposity.